Investigation of energy efficiency in Gebze Wastewater Treatment Plant

An intensive amount of energy is used during the operation of wastewater treatment plants, depending on the processes and equipment employed. The equipment which exhibits a large scale of diversity varies widely in their energy requirements as well. Energy costs constitute the most important part of the budget in the operation of a treatment plant. The issue of energy conservation has become a crucial topic for wastewater treatment plants as the energy costs are on a rising trend in Turkey. This study is conducted to investigate the energy efficiency of Gebze Wastewater Treatment Plant located in Gebze district of Kocaeli by assessing the influent and effluent design and operation parameters of the plant and to determine unit energy consumption values required for treating a unit amount of wastewater. In the plant, removal of many contaminants like chemical oxygen demand, biological oxygen demand, suspended solids, total nitrogen and total phosphorus has been aimed. Approximate removal efficiency of chemical oxygen demand, biological oxygen demand and suspended solids is determined to be 93%, 98% and 94%, respectively. Total amount of treated wastewater was 2,020,723 m3/month on average, and total amount of electricity consumption of the plant is 819,754 kWh/month on average. The consumption of electricity used for treating 1 m3 of wastewater varies between 0.38 and 0.43 kWh. Although the amount of total energy use increases depending on the amount of pollutants in the incoming water and treated pollutants, unit energy costs decrease as expected.